Method for intermediate unlocking of a keypad on a mobile electronic device

ABSTRACT

A method and device for changing input states of an electronic device, the device comprising an input portion and being capable of carrying out user operations, the input states comprising a locked state, where the use of the input portion is significantly restricted, and an unlocked state, where the use of the input portion is not restricted, the locked and unlocked states being respectively enterable by a locking and unlocking input. A further input state is an intermediate unlocked state in which a limited operational use of the input portion is possible; which method comprises entering the intermediate unlocked state from the locked state, based on user input; detecting termination of a user operation in the intermediate unlocked state, and entering the locked state, in response thereto. There is also provided an input controller, a keypad and a mobile electronic device implementing these features.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is for entry into the U.S. national phase under §371for International Application No. PCT/IB02/00623 having an internationalfiling date of Mar. 2, 2002, and from which priority is claimed underall applicable sections of Title 35 of the United States Code including,but not limited to, Sections 120, 363 and 365(c).

TECHNICAL FIELD

The present invention relates to electronic devices having input means.It also relates to mobile electronic devices having lockable input meansto prevent inadvertent input.

BACKGROUND OF THE INVENTION

In many popular mobile terminals of today, the keypad can be locked whenthe phone is not used. There are many ways to implement the keypad lockfeature, the most popular terminals using a sequence of two differentkey-presses to lock the keypad, and some other terminals having featureslike timer lock or keypad lock selection from the menu. Also, thepossibly existing cover of the keypad can be used for locking, or thekeypad can be locked when other input options of the electronic deviceare used.

It is known that the keypad of a mobile phone (or similar device) can belocked e.g. by selecting such an option from a menu or by pressing acertain key combination. The key-locks are used to prevent accidentalkey-presses, for example if the device is in a pocket or in a purse.However, sometimes the user would like to use the device only for onequick operation, e.g. to read a received SMS (Short Message) or tochange the user profile. If the keypad is locked, in ordinary mobileterminals, the user has to unlock the keypad first, then perform theoperation and in the end remember to lock the keypad again.

Prior art U.S. Pat. No. 4,845,772 (Motorola) discloses a mobile phonewhere the keypad is automatically locked following an operationperformed by the user (closing a flip element). However, this manner ofoperation is tied closely to a phone containing a flip element.

Nokia patent application EP 0 939 533 discloses a semi-automatickey-lock where upon closing a sliding cover a softkey for locking thekeypad appears on the screen.

Both approaches for key-locks described above have in common that theyare not suitable for the use with mobile terminal devices or handheldcomputers that do not have slideable or flippable covers. Therefore, theabove mentioned electronic communication devices fail to overcome theproblems related with cover-less mobile electronic devices.

The current solutions, although providing a secure locking mechanism,hamper the use of the terminal for quick operations, while they providethe necessary key-lock function. For example, when the user wants to usethe terminal for a single phone call, or if he wants to change theprofile of the terminal or to read a received SMS, it is first necessaryto unlock the keypad (e.g., two key-presses and a short waiting time),then maybe press a single key to perform the function (dial shortcut,select profile, show message) and after the operation, press two keys tolock the keypad or wait for the lock timeout. This cumbersome operationoften leads to user's negligence that the keypad is left unlocked, thisin turn perhaps leading to accidental phone calls. While the timer locksolves this problem partly, there is still the timeout period whenrandom key-presses can initiate calls or interfere with the operation ofthe terminal otherwise, e.g. by terminating a call in progress orentering names into the phonebook.

SUMMARY OF THE INVENTION

It is therefore desirable to provide an input lock mechanism that can beoperated faster to perform a single quick task.

It is desirable to provide a method and a device to ensure that a userdoes not forget to lock an electronic device after use to prevent thewaste of resources.

It is desirable to have an electronic device that is capable of lockingitself automatically.

According to a first aspect of the present invention, there is provideda method of changing the input state of an electronic device. The devicecomprises input means and is capable of carrying out user operations.The input states comprise a locked state, where the use of the inputmeans is significantly restricted, an unlocked state, where the use ofthe input means is not restricted, and an intermediate unlocked state.The locked state can be entered by a locking input, and the unlockedstate can be entered by an unlocking input. The method comprises thesteps of entering said intermediate unlocked state based on user input,detecting the termination, completion or other ending of a useroperation in said intermediate unlocked state, and entering said lockedstate, in response to said detection, wherein said user operation isother than said locking input. Preferably the intermediate locked statecan be entered by an intermediate unlocking input.

According to this embodiment, e.g. the keypad is intermediately unlockedor cleared for user input by an intermediate unlocking input, e.g. acertain key combination, and then there is at least one or there aresome predefined user input steps that can be performed. When such anoperation is detected as (successfully) completed, i.e terminated, theinput means is automatically re-locked again. Alternatively, when suchan operation is cancelled, the input means is automatically re-lockedagain. Altogether, if it is detected that the operation has ended eitherby completing it or cancelling it, or the phone otherwise entering astate, where it can be determined that the user is not continuing theoperation anymore, the input means is automatically re-locked again. Insummary, there is provided an intermediate unlocked state of the inputin which only a limited operational input is possible. Once saidoperational input is finished the device is relocked again.

The method according to an embodiment of the invention provides anintermediate unlock operation which re-locks an electronic deviceautomatically, if a predetermined auto-locking definition is met.Preferably, the method would be used in an electronic device that offerstwo different unlocking modes, i.e. a general unlock, which requires asecond user input to lock the electronic device (a locking input) as inthe case of the known mobile telephones, and a limited unlock operationwhich locks the electronic device automatically if a predeterminedauto-locking definition is met, the auto-locking definition being otherthan the locking input mentioned above. The electronic device may beconfigurable to offer both unlocking features simultaneously orexclusively. A user may be able to select the default unlock mode e.g.from the device settings.

According to an embodiment of the invention the method can be executedin a shortened form, e.g. if certain operations can be accesseddirectly. The intermediate unlock input can be a key sequence to e.g.display a message (e.g. SMS or MMS, or an e-mail), pressing the keysequence to view the message e.g. the access is limited to “read only”,and following the depiction of the SMS the device locks itselfautomatically, i.e. either in a state of depicting the SMS or in a stateof automatic return to the default display. Another example for this“fast” access can be e.g. for a mobile telephone device (MTD) userentering a change of the alarm from “tone” to “vibration”, so that auser does not have to waste time for unlocking the device to silence theMTD e.g. if the user forgot to switch the sound off while watching afilm in a cinema. In this particular mode, it seems to the user that theMTD can be operated without an explicit unlock code to be entered.Preferably, said limited access restricts the access to a small numberof possible input operations. This limitation can be used to grantaccess only to a few and especially only low resource consumingoperations.

According to an embodiment of the invention, the invention can beimplemented e.g. as follows: a group of state traversal lists is definedthat can follow the intermediate unlock input like key-presses. Onlysuch a sequence of key-presses that can actually traverse a list areallowed to be carried out. If the user presses a key that is notassigned to the state lists at that step, the keypad is immediatelylocked up. This can be realised by organising the information of all thestate traversal lists into a tree-like structure of states. The tree istraversed from root up by moving to the next state with each key-press,or with certain predefined key-presses. When the terminal enters a statethat is a final leaf on the tree or outside the tree, the terminal islocked up again.

The internal states of the tree can include a free-text entry mode,wherein exiting the state is not defined by any number of key-presses,but instead the state is exited by selecting an operation to be carriedout to the text, e.g. “send”, “save” or “delete”, or by cancelling theinput operation, e.g. by pressing the “cancel” button on the keypad.

It is to be noted that the “freely usable” intermediate unlock sequencesmay be programmable by the user, thereby ensuring that the inputsequence following limited unlocking is a user-specific operation.

It is to be noted, that a sign or a text on the display can be used toalert the user that the device is operating in an intermediate unlockedand/or in a limited access mode. Alternatively the method furthercomprises a step of indicating on the screen, that the temporary unlockfeature is in use. This may be embodied by e.g. by a flashing lock sign,or a count down timer indicating the remaining intermediate unlockedtime. This feature may include the depiction of available andunavailable soft-keys or menu elements.

Preferably, the method comprises the steps of receiving an input,executing said input, ending said input and re-locking the device. Thesesteps enable the method to use an input related auto-locking definition,to activate the auto-lock automatically, e.g. after a predeterminedinput. The predetermined input can be e.g. defined by a finally executedaction, like changing a configuration, executing a single telephonecall, reading and deleting or even answering an SMS. This embodiment ofthe invention offers a method to unlock the terminal keypad, operate theterminal for just a few consecutive and operationally related functionsusing the keypad, and have the terminal lock up its keys immediatelyfollowing the last related key-press.

Advantageously, said intermediate unlocked state restricts the access toa subgroup of the user operations that can be carried out. This meansthat the electronic device unlocks only for predefined actions to beexecuted in the intermediate unlocked state. So e.g. a fast two stepintermediate unlock input may only grant access to the basic functionsof the mobile telephone. In the case of a mobile telephone the basicfunctions can be e.g. the telephone operability, for people using amobile telephone like a “portable” call box. For people using theirmobile phone more like a PDA (Personal Digital Assistant), the basicfunctionality can be e.g. the calendar or timer functionality. Theelectronic device can offer the option of a selective basicfunctionality, so a user may select e.g. via a menu which basicfunctionality is accessible in the intermediate unlocked state. Theunlocking only for predefined actions can be executed in dependence ofthe operation state of the electronic device. For example, thepossibility to read a SMS message could be added to the list ofaccessible operations only when there is actually an unread SMS message.

According to a preferred embodiment of the present invention thetermination or ending of the user operation is one of the group:completing the user operation, cancelling the user operation, detectingthe idleness of user input and detecting an unexpected user input.

The locked state in an electronic device can be entered by the steps of:detecting idleness or the absence of user input, and entering the lockedstate. This locking operation may be operated in the unlocked state andthe intermediate unlocked state of the electronic device.

The locked state in an electronic device can be entered by the steps of:detecting unexpected user input, and entering the locked state. Thislocking operation can be operated in the unlocked state and theintermediate unlocked state of the electronic device.

This embodiment of the present invention can be used, e.g. in connectionwith standard key-unlock functionality, and may be switched on and offvia the menu “settings” of the electronic device. This functionalityenables e.g. to detect if an input is caused by an intelligent andauthorised user or if it seems to follow a more or less arbitrary inputpattern. This feature is easy to implement, as e.g. mobile telephonesand other electronic devices can recognise a valid and invalid input andsignalise the acceptance or the rejection of an input with differentsound signals. So an invalid input counter can e.g. be connected withthe key-unlock functionality, to reactivate the key-lock at the first,second or third invalid input. The “invalid” input counter may be resetat each first, second or third valid input or according to a timer.

Conveniently, said detection of termination or ending of the useroperation is defined by a predetermined number of input operations. Thelocked state is entered after e.g. a predetermined number of inputoperations and/or to a defined number of executed operations. Thedetermined number can be a fixed natural number or the number can berelated to the respective operation. So the input need not only berestricted to certain kinds of input but can e.g. be restricted to theexecution of a single operation.

Advantageously, said detection of ending of the user operation is timerelated. The access in the intermediate unlocked state can be timelimited as in the case of timer related auto-locking functionality. Thetime related intermediate unlocked state can provide an additionalsafety element to prevent e.g. unintentional inadvertent dialling. So atelephone can enter the locked state in both cases: if e.g. a timer runsout, or if the end of a user operation is detected. The time relation ofthe intermediate unlocked state can be e.g. an absolute time relation,like a timer started with the detection of the intermediate unlockinginput, that is only reset in the case of a re-locking of the device.Such a timer is related to the intermediate unlocking operation and mayhave a run time of e.g. 5 min. The timer may be reset at any input. Sucha timer is related to the intermediate unlocked state and can comprise atime interval of e.g. a few seconds or a few tens of seconds.

Preferably said intermediate unlocking input required for entering saidintermediate unlocked state, i.e. a certain key sequence, is differentfrom the unlocking input required for entering the unlocked state, andis also different from the locking input required for entering thelocked state. So it is at least one predetermined key sequence.Preferably there are more than one key sequences for intermediatelyunlocking the device for a variety of intermediate unlocked states, e.g.one predetermined key sequence for entering an SMS reading intermediateunlocked state, and another key sequence for entering an SMS composeintermediate unlocked state.

According to another aspect of the present invention, a software toolfor carrying out the method for entering a locked state from anintermediate unlocked state, upon detecting of a termination or anending of a user operation, of an electronic device is provided, whichcomprises program code means for performing all of the steps of thepreceding description when said program is run on a computer or anetwork device.

According to another aspect of the present invention, a computer programfor carrying out the method for entering a locked state from anintermediate unlocked state, upon detecting an ending of a useroperation, of an electronic device is provided, which comprises programcode means for performing all of the steps of the preceding descriptionwhen said program is run on a computer or a network device.

According to yet another aspect of the invention, a computer programproduct is provided comprising program code means stored on a computerreadable medium for carrying out the method for entering a locked statefrom an intermediate unlocked state of an electronic device upondetecting the ending of a user operation, of the preceding descriptionwhen said program product is run on a computer or a network device.

According to yet another aspect of the invention, an input controllerfor an electronic device is provided, for changing the input state of anelectronic device. The input controller comprises: means to operativelyconnect an input means to said input controller, means to operativelyconnect a computing means of an electronic device to said inputcontroller, means to enter the intermediate unlocked state based on userinput, means to detect the termination or ending of a user operation,and means to lock said input means in accordance with said detectedtermination or ending of a user operation.

An input controller is a hardware (or software) device operativelyconnected between input means and the executing (processing) means of anelectronic device, e.g. to convert the signals from single keys of akeypad to computable digital code. The input controllers of computerscan be found e.g. in the keyboard as a piece of hardware and in thecomputer as a piece of software. The input controller can e.g. lock akeyboard according to a certain input, as it is capable ofpre-processing expected keypad input. The input controller can e.g. locka keyboard according to a certain input from the computing means. Theinput processing capability enables the input controller to perform theentering of the intermediate unlocked state based upon user input, andto check input for the termination or the ending of a user operation andlock the keyboard by itself, without the need to request the processingmeans of the electronic device. The input means can be integrated in anelectronic device. The input means can be an external input means suchas a separate keyboard or e.g. a remote control device integrated e.g.in a wristwatch. The external input means can be connected to the devicevia a slot, a wired connection or by a wireless connection such asBluetooth.

Preferably, said input controller further comprises a timer. A timerenables the keypad controller to e.g. autonomously lock the keypad aftera predetermined time following previous detected unlocking input orgeneral input.

According to another aspect of the present invention, a keypad isprovided that comprises an input controller as previously described. Askeyboard and keypads nowadays are designed as integrated units on asingle circuit board, a limited unlocking and auto-locking feature canbe added to different electronic devices by simply applying a keyboardaccording to the present invention. The keyboard can be a built-in or anexternal keyboard or keypad.

According to another aspect of the present invention, an electronicdevice, e.g. mobile terminal device, is provided that is capable ofexecuting the preceding methods for intermediate unlocking. Theelectronic device capable of intermediate unlocking comprises inputmeans, and different user input states. The input states comprise alocked state, where the use of the input means is significantlyrestricted, and an unlocked state, where the use of the input means isnot restricted, the locked state being enterable by a locking input, andthe unlocked state being enterable by an unlocking input, and anintermediate unlocked state. The device further comprises means forentering said intermediate unlocked state based on user input, and meansfor detecting the termination or ending of a user operation in saidintermediate unlocked state, the user operation being other than saidlocking input, and means to enter a locked state once said terminationor ending has been detected. The electronic device can e.g. be anelectronic terminal device, like a mobile telephone or a communicator, aPDA, a portable computer, or any other multipurpose electronic device(desktop computer, home accessory, etc.). The intermediate lock featurecan be integrated in single-purpose devices too. Multi-purpose devicesbenefit the most from the ability to execute the previously describedlimited unlocking and/or auto-locking of the whole device or only ofsingle applications.

Advantageously, the electronic device further comprises a memory tostore predefined inputs to lock, intermediate lock and unlock thedevice, or different terminations of user operations. With a memory forpredefined inputs, the device can provide different and e.g. userselectable inputs to be used as an unlocking input sequence. The memorymay be utilised to store auto-locking definitions as well.

Preferably, the electronic device further comprises a timer, forexecuting timer related detecting of termination or ending of useroperations, as in the case of the input controller.

Preferably said user input required for entering said intermediateunlocked state is different from the unlocking input and the lockinginput, as described above, and comprises at least one predetermined keysequence.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in detail by referringto the enclosed drawings in which:

FIG. 1 is block diagram depicting a mobile telephone providing anintermediate unlocking feature according to one embodiment of thepresent invention,

FIG. 2 is a flowchart of an intermediate unlocking algorithm of anelectronic device according to one aspect of the present invention,

FIG. 3A is a diagram depicting a conventional menu input tree,

FIG. 3B is a diagram of the menu input tree of FIG. 3A with in theintermediate unlocked state with limited accessibility, and

FIG. 4 is a flowchart illustrating the use of a the intermediateunlocking method according to another embodiment of the presentinvention.

DETAILED DESCRIPTION

FIG. 1 is block diagram depicting a mobile telephone 200 providing anintermediate unlocking feature according to one embodiment of thepresent invention. The mobile telephone 200 has a keypad 222, a display212, a loudspeaker 232 and a microphone 234, like any usual mobiletelephone, the keypad 222 is connected via the input or keypadcontroller 220 to a mobile or central processing unit MCU 230. The MCU230 is connected via the display controller 210 to the display 212. Themobile telephone further comprises a memory 232, that is at leastconnected to the MCU 230, and that may be connected to the keypadcontroller 220. The MCU is further connected (not shown) to othertelephone elements (not shown) such as e.g. baseband processing means,transmitters, receivers, antennas and the like. The connection betweenthe keypad controller and the central processing unit is bi-directional.

The keypad controller 220 pre-processes input from the keypad 222 beforetransferring it to the MCU 230. The keypad controller 220 can lock orunlock the keypad 222, in dependence of input from the keypad 222, or ofsignals from the MCU 230. So if e.g. a user presses keys on the keypad222 of the mobile phone, the keypad controller 220 transforms the inputinto digital code, readable by the MCU. The keypad controller can beenabled to lock the keypad if it detects a predetermined input sequencee.g. “menu-star” with the effect that the keypad controller does notforward further keypad input to the MCU 230, until the keypad controller222 detects an unlocking sequence, e.g. “menu-star”. The keypadcontroller may forward a signal to the MCU 230 indicating invalid input,so that the MCU 230 may forward a signal via the display controller 210to the display 212 to depict e.g. a “keypad locked” sign or a respectivetext. The mobile telephone according to this embodiment of the inventionis capable of recognising different unlock sequences leading todifferent accessibility of the device. In the embodiment depicted in thefigure, the different unlocking sequences are stored in the memory 223,so the keypad controller 220 can recognise different input sequenceswithout the need to contact the MCU 230 which can stay in e.g. in a lowpower mode, until it receives a signal from the keypad controller, thata certain unlocking code has been received.

The keypad controller 220 acts like a doorkeeper rejecting all exceptcertain predefined inputs and only wakes up the MCU 230 if a certaininput is recognised. The connection between the MCU 230 and the memory223 enables the MCU to change the valid unlock sequences, and may beused to store information about the number of possible inputs and of thekind of granted access.

It is to be noted that the keypad controller 220 and the memory 223 maybe embodied as a software application running on the MCU.

FIG. 2 depicts a flowchart of an intermediate unlocking of an electronicdevice. In step 2 the device is in a default key-locked state, likeusually a mobile telephone carried in a pocket is. In step 46, theelectronic device receives an input, e.g. from the telephone keyboard.In step 8 the input is checked for unlocking sequences. The input ispreferably buffered before the checking, so that the entire inputsequence can be written into a buffer before checking the input for(intermediate) unlocking sequences. If no unlocking sequence is found,the device returns to or stays in the locked state 2. If a generalunlocking sequence is recognised, the general unlock is activated (notshown) until the general key-lock sequence is entered. If the checkingoperation 8 recognises a sequences of key-presses for intermediateunlocking of the electronic device, the electronic device enters theintermediate unlocked state 12. In the state 12 the device can receivedifferent user input within predetermined limits. The limit can be e.g.the number of executable actions, operations or change of settings orthe like. In the state 12, following to every input, it is checked 14,if the user operation has ended. If the user operation has not ended,the device returns in to the state of limited access 12. If the useroperation has ended, the device is automatically locked and returns into the locked state 2.

A classic unlock input sequence of an electronic device e.g. for NOKIA®mobile telephones is “menu-star”. This sequence is the only combinationof keys to unlock the phone in the locked state. The phone has 18 keysso the probability of a coincidental unlocking is 1 to 324. In practicethe probability is even smaller, as 1 to 324 is the probability when tworandomly selected keys are pressed successively. But when a mobileelectronic device is carried e.g. in a pocket, and for some reasonpressure is applied to the keypad, the probability that exactly two keysare pressed successively (and not the same time) is already quite small.The desired intermediate unlocking feature should not increase thisprobability significantly. The desired intermediate locking state can beentered e.g. by an additional key input not used by e.g. an otherfrequently used input like the menu key or an abbreviated diallingfeature like the keys 0 to 9. The intermediate unlocking key sequencecan be e.g. “menu-star-star”, “menu-star-pound”, “menu-menu-star”, orgenerally “x-menu-star”″, where x is any key. The intermediate unlockingkey sequence can be simply “star-menu” or “menu-pound”, wherein “#” isthe “pound” sign. The pattern could be “hold menu-star”, where the menukey must be held for 2 seconds. In the case of the first two three-stepsequences “menu-star-star”, “menu-star-pound”, the sequence “menu-star”unlocks the electronic device and the following “star” or “pound key”activates the intermediate unlocked state. In the case of the twotwo-step sequences, the sequence “star-menu”, or “menu-pound” directlyenters the intermediate unlocked state of the electronic device. Thethree step sequences have the advantage that the probability of acoincidental unlock is the same as before, and the advantage of simplerimplementation. The two step sequences have the advantage of fasterunlocking.

When the intermediate unlocked state is in effect, the user can e.g.carry out one task, i.e. one sequence of key-presses, and when thatsequence is completed, the keypad is automatically locked again. Forexample, when there is a new message, the user can press“menu-menu-star-menu” to view the message (if implemented, e.g. onNOKIA® mobile telephone 8310). In the sequences the double hyphenindicates the borderline between the unlock sequence and the inputsequence for operations. A sign on the screen is used to indicate thatthe intermediate unlocked state is entered. When the user exits themessage (red button or exit), the SMS menu is exited, and the keypad islocked.

To give another example, the user can press “menu-menu-star-2” to dialthe first fast dial number, the keypad will be immediately locked, andif the user is using a headset, there is no problem dropping the phoneinto the pocket, since the keypad is locked. This option can be providedas NOKIA® headsets have a “receive and terminate phone calls” key, whichis not locked automatically. To give yet another example, the user canpress “menu-menu-star-power-power-power-menu” to enter silent mode andhave the keypad automatically locked without having to remember lockingit.

It is to be noted that the scope of the present invention is not limitedto the described intermediate unlock sequences. The number of validintermediate unlock input sequences can be e.g. two as mentioned in thedescription of FIG. 1. The number of valid intermediate unlock inputsequences can be unlimited and be e.g. user selectable, so that e.g. auser can e.g. configure the telephone to accept “5-5-5” or “7-7-7”resembling a hissing sound e.g. as valid input sequence for unlockingand entering the game application “Snake” of a mobile telephone. Thevalid input sequence for unlocking can be combined with a “skip”functionality so as to economise further input for the limited access ofe.g. a single application.

FIG. 3A is a tree diagram depicting a conventional menu input tree,wherein the standard operation state is depicted as the box 100. Thestate 100 is the standard operation state, with the main options ofcalling operations 101. The calling operations can be e.g. a “standarddialling operation” 111, an “abbreviated dialling operation” 112, a“dial last number”, a “voice dialling operation” 110 or the like. Therectangle 102 indicates the state of an activated menu. The menu box 102offers menu elements e.g. “voice box or voicemail box” 124, “messages”122 “settings” 128 and the like. The menu “voice box” 124 furthercomprises e.g. the submenu items “voice box alert” 136, “voice boxnumber” 138, “call voice box”, and the like. Wherein “voice box alert”136 comprises the submenus “alert on” 150 and “alert off” 152 and“vibration alert” 154 and further options. Wherein “voice box number”138 comprises the submenus like “change number” and “confirm number”.Wherein “call voice box” comprises no further submenu as the activationof “call voice box” starts the terminal operation of calling the voicebox.

The menu messages 122 further comprises the sub menu items “inbox” 130,“outbox” 132, and “settings” 134. Wherein “inbox” 130 comprises thesubmenu items as “reply/forward” 140 and “read/delete” 142. Wherein“outbox” 132 comprises the submenu items as “send/edit” 144 and“read/delete” 146. Further submenus e.g. of 140, 142 are not depictedfor the sake of clarity. The menu and submenu elements are connectedwith bi-directional arrows to indicate that the menu can be used in alldirections, so that it is possible to return from a sub menu elementback to the “master/mother” menu.

FIG. 3B is a tree diagram of the menu input tree of FIG. 2A in the caseof an intermediate unlocked state with a limited accessibility, e.g.because of a limited unlocking of the electronic device. Basically, themenu structure is the same as in FIG. 2A. But there are threesignificant differences: the number of accessible menu elements islimited, the connections of the menus elements are mono-directional, andthe terminal menu elements are connected to the box 199.

The number of accessible menu elements is restricted to certainoperations, in the present case to the message menu. After anintermediate unlocking operation, the user can select the menu 102,further select the message menu 122, as in the case of the generalunlocking. In difference to the state of a general unlocking the menuelements 101, 124, . . . ,128 are not accessible, and therefore depictedin dotted lines. These dotted menu elements are not accessible forreasons such as that the elements are irrelevant in the current state ofthe phone, that it could be resource consuming to activate them, and thelike.

The use of menus can be restricted as the connections are directed fromthe menu to submenu, so that a user can select a submenu but can notreturn to the master/mother menu directly. This is indicated by themono-directional arrows connecting the single menu elements.

All terminal menu elements are mono-directionally connected with the box199. The box 199 is a locked state that is entered, if a terminal menuelement is reached or the operation of a terminal menu element iscompleted.

The user benefits from the invention that he doesn't have to remember tolock the keypad after unlocking and using electronic devices. Theinvention improves the feel of the terminal by converting three-stepoperation of a quick task to a two-step operation: from “unlockkeypad”—“perform task”—“lock keypad” to “unlock keypad”—“perform task”.Moreover, the user is less likely to forget locking the keypad.

FIG. 4 is a flowchart illustrating the use of an intermediate unlockingalgorithm according to another embodiment of the present invention. Theflowchart comprises three states: a locked state 20, an intermediateunlocked “select operation” state 22 and a “write short message” state24. Starting from the locked state 20 a user can unlock the device byinputting an intermediate unlock key sequence in step 30, and reach the“select operation” state 22. In the state 22, the user can browse 34e.g. a menu tree structure up and down different levels. In the state 22the user can make more complicated operations than just once selectingsomething from a menu, and the user can move in the menu and there arenot only one way inputs, to the “next level” in the hierarchy. Therecould be a possibility to go back and forth in the accessible parts ofthe menu (at least to some extent). In the state 22 the user can exit 32the selection state 22 back to the locked state 20.

In the state 22 the user can select a “one way operation” by e.g.selecting 36 the “write short message” option 24. There can be other“one way” selectable operations such as change settings, change alarmtone and suchlike, these options are not depicted for the sake ofclarity. In the state 24 the user can write a short message, or anyarbitrary sequence of characters, and edit the message, in a “free text”mode indicated by the step 38. The user can send 40 the short message,and thereby entering the locked state of the device, and return to thelocked state 20. The user can exit the state 24 by cancelling the actionand can directly return to the locked state 20.

The invention complicates only slightly the implementation of theterminal, and the functions for which the intermediate unlock feature isused should be defined clearly to or by the user.

It should be noted that the method can be used for example withtouchscreen displays. In this case there can be similar kind of featurethat would allow only certain operations to be carried out. Startingwith a “locked” touchscreen, a user opens the lock with the intermediateunlock code, and only the available softkeys are shown. These softkeyscan be displayed as larger than in situations when the device is fullyunlocked and all softkeys are visible. This feature can be used withvoice commands, too. When the intermediate unlocked mode is activated,only certain commands may be executable. The device may indicate thatonly a limited number of voice commands are available in the limitedunlocked state. With such a solution the detection accuracy can beimproved since there are fewer possible commands that can be carried outin the limited unlocked state.

This application contains the description of implementations andembodiments of the present invention with the help of examples. It willbe appreciated by a person skilled in the art that the present inventionis not restricted to details of the embodiments presented above, andthat the invention can also be implemented in another form withoutdeviating from the characteristics of the invention. The embodimentspresented above should be considered illustrative, but not restricting.Thus the possibilities of implementing and using the invention are onlyrestricted by the enclosed claims. Consequently various options ofimplementing the invention as determined by the claims, includingequivalent implementations, also belong to the scope of the invention.

1. A method of changing the input states of an electronic device, havingan input portion, the device capable of carrying out user operations,and the device having input states including a locked state, wherein theuse of the input portion is significantly restricted, and an unlockedstate, wherein the use of the input portion is not restrictedcomprising: entering the locked state by a locking input, entering theunlocked state by an unlocking input, entering an intermediate unlockedstate of said electronic device, in which a limited operational use ofsaid input portion is possible, from the locked state, based on anintermediate unlocking user input which is different from the unlockinginput required for entering the unlocked state; detecting thetermination of a user operation in said intermediate unlocked state, theuser operation being other than said locking input and including thecompletion of at least one task by a number of input operations greaterthan one; and entering said locked state, in response to said detection.2. A computer program product comprising program code stored on acomputer readable medium for carrying out the method of claim 1 whensaid program code is run on an electronic device.
 3. A mobile electronicdevice comprising: an input portion; different user input states, theinput states including a locked state, where the use of the inputportion is significantly restricted, said locked state being enterableby a locking input, and an unlocked state, where the use of the inputportion is not restricted, said unlocked state being enterable by anunlocking input, an intermediate unlocked state in which a limitedoperational use of said input portion is possible, wherein theelectronic device is adapted to enter the intermediate unlocked statebased on an intermediate unlocking user input which is different fromthe unlocking input required for entering the unlocked state; adapted todetect the termination of a user operation in said intermediate unlockedstate, the user operation being other than said locking input andincluding the completion of at least one task by a number of inputoperations greater than one; and adapted to enter said locked state inresponse to said detection.
 4. The mobile electronic device according toclaim 3, further comprising a memory to store locking, unlocking andintermediate unlocking inputs.
 5. The mobile electronic device accordingto claim 4, further comprising a timer.
 6. The mobile electronic deviceaccording to claim 3, further comprising a timer.
 7. A mobile electronicdevice comprising: means for user input; means for providing differentuser input states, the input states including a locked state, where theuse of the means for user input is significantly restricted, said lockedstate being enterable by a locking input, and an unlocked state, wherethe use of the means for user input is not restricted, said unlockedstate being enterable by an unlocking input, and an intermediateunlocked state in which a limited operational use of said means for userinput is possible, means for entering the intermediate unlocked statebased on an intermediate unlocking user input which is different fromthe unlocking input required for entering the unlocked state; means fordetecting the termination of a user operation in said intermediateunlocked state, the user operation being other than said locking inputand including the completion of at least one task by a number of inputoperations greater than one; and means for entering said locked state inresponse to said detection.